1. Field of the Invention
The present invention relates to a piezoelectric element which extends and contracts when electric signals are inputted thereinto and a driving apparatus which utilizes the piezoelectric element.
2. Description of the Invention
As the related-art driving apparatus which utilizes a piezoelectric element, there is known, as is described in the Japanese Patent No. 2633066, a driving apparatus in which a drive rod is caused to reciprocate in response to extension and contraction of a piezoelectric element, so as to move a lens barrel which is in frictional engagement with the drive rod along the drive rod. In the piezoelectric element which is used in the driving apparatus, for example, as is shown in FIG. 7, an extendible and contractible portion 103 which extends and contracts is disposed in such a way as to be held by two electrodes 101, 102 therebetween. Lead wires 104, 105 are connected to the belt-shaped electrodes 101, 102, respectively, so that electric signals are inputted into the piezoelectric element though these lead wires 104, 105.
In the driving apparatus and the piezoelectric element like these, however, there may occur a problem that extending and contracting operations of the piezoelectric element are not performed with good efficiency. Namely, since the lead wires 104, 105 are connected to side portions of the extendible and contractible portion of the piezoelectric element, the connecting portions of the lead wires 104, 105 interrupt the extending and contracting motions of the piezoelectric element, leading to the problem that the originally designed operation of the piezoelectric element cannot be performed sufficiently. In particular, when the lead wired 104, 105 are connected to the piezoelectric element through soldering, there may occur a risk that the extending and contracting motions of the piezoelectric element vary depending on the solder connecting state of the lead wires 104, 105.